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The Effect of Digestion and Digestibility on Allergenicity of Food (first part)

by luciano

“Abstract: Food allergy prevalence numbers are still on the rise. Apart from environmental influences, dietary habits, food availability and life-style factors, medication could also play a role. For immune tolerance of food, several contributing factors ensure that dietary compounds are immunologically ignored and serve only as source for energy and nutrient supply. Functional digestion along the gastrointestinal tract is essential for the molecular breakdown and a prerequisite for appropriate uptake in the intestine. Digestion and digestibility of carbohydrates and proteins thus critically affect the risk of food allergy development. In this review, we highlight the influence of amylases, gastric acid- and trypsin-inhibitors, as well as of food processing in the context of food allergenicity.
Omissis…..Furthermore, digestion and digestibility could determine whether food proteins are tolerated or become sensitizing agents. This aspect has therefore even been taken up by the European Food Safety Agency in their scientific opinion about evaluation of allergenicity of food and feed proteins. Higher resistance to digestion or survival along the digestive tract seems to increase the sensitization capacity of a food component and renders it more immunogenic and/or allergenic. Based on this scientific background, the present review article highlights factors influencing protein digestion and digestibility.

From the study:

Digestion of Carbohydrates: Amylase Action Critical for Starch Digestion and Microbiome

……..Omissis. Starch is digested by specific enzymes, i.e., amylases, which cleave the α-1,4-glucosidic bond of its major compound amylose, as well as the α-1,6-glucosidic bond of the second major constituent, amylopectin [15].

….. Omissis. In humans, α-amylase is a product of the exocrine pancreas. Animal models suggest that microbial amylases could be supplied in pancreas insufficiency [18]. It is not known whether this will be linked to a risk for sensitization, but α-amylase per se when inhaled is a well-known occupational allergen. In baker’s asthma associated with the flour processing industry, allergenic amylase derives from contaminating fungi [19]. In mammals, amylase is also secreted into the saliva. Its role in starch digestion has been questioned due to its low amount relative to the overall amylase activity [20]. However, in vitro studies strongly propose that salivary amylolytic activity hydrolyzes up to 80% of bread starch in the first 30 min of gastric digestion, independent of acidification by the gastric juices [21]. This critically affects the quality of remnants reaching the intestine, which will affect the composition of the microflora (discussed below).

………Omissis. The amylase action on rapidly digestible starch (RDS) renders smaller products, like disaccharides and trisaccharides [25]. These are then further hydrolyzed to glucose by other enzymes, such as α-glucosidase in the small intestine [26]. However, both amylase and α-glucosidase may act synergistically. Some compounds represent slow-digestible starch (SDS), or resistant starch (RS) as larger leftovers, which persist the gastrointestinal transit to a large degree. Usually, resulting levels of malto-oligosaccharide indicate the degree of granular starch breakdown. The starch breakdown by amylases is largely influenced by the composition of the food processing and matrix composition. Cooking has been shown to enhance the amylase breakdown of starch [27], which also depended on the individual α-amylase activity. Flavonoids are important plant constituents, which interfere with amylase activity by hydrophobic interaction in the food matrix or by formation of covalent bonds during cooking or in gastric juice, and therefore impair starch digestion [28]. This opens up potential intervention strategies in diabetic patients to decrease the fermentation speed of starch and thereby inhibit an undesired fast release of glucose. Starch may also form complexes with lipids in the food matrix, e.g., complex formation with palm oil interfered with the digestion of rice starches [29]. Interestingly, some fresh food may neutralize amylases by proteolysis. Kiwi contains actinidin, a cysteine proteinase, which specifically attacks amylase and thereby may inhibit starch digestion [30]. This may affect the presentation of allergenic epitopes in the food matrix. Amylase in the duodenum also plays a key role in the breakdown of gluten and may therefore modulate its pathophysiologic role in celiac disease [31]. While starch forms complexes with gluten during baking of bread, amylase resolves them and makes gluten accessible for thorough protein digestion. Wheat on the other hand contains anti-enzymes, such as the ATIs (amylase-trypsin inhibitors) with a role in non-celiac gluten sensitivity (NCGS) [32]. Nutritional ATIs additionally stimulate the innate immune reaction via TLR4 [32] and thereby exacerbate allergic inflammation not only in the intestine, but also in the airways in mouse models [33,34]. It is hypothesized that industrial food processing contributes to the increased numbers of non-celiac gluten/wheat sensitivity by stabilizing e.g., starch-gluten complexes, thereby bypassing the salivary and pancreatic enzymes, leaving the digestion to mucosal amylases [35]”. “The Effect of Digestion and Digestibility on Allergenicity of Food Isabella Pali-Scholl, Eva Untersmayr, Martina Klems and Erika Jensen-Jarolim. Published: 21 August 2018 Nutrients.”

FODMAPs: food composition, defining cutoff values and international application

by luciano

Abstract
The low-FODMAP diet is a new dietary therapy for the management of irritable bowel syndrome that is gaining in popularity around the world. Developing the low-FODMAP diet required not only extensive food composition data but also the establishment of “cutoff values” to classify foods as low-FODMAP. These cutoff values relate to each particular FODMAP present in a food, including oligosaccharides (fructans and galacto- oligosaccharides), sugar polyols (mannitol and sorbitol), lactose, and fructose in excess of glucose. Cutoff values were derived by considering the FODMAP levels in typical serving sizes of foods that commonly trigger symptoms in individuals with irritable bowel syndrome, as well as foods that were generally well tolerated. The reliability of these FODMAP cutoff values has been tested in a number of dietary studies. The development of the techniques to quantify the FODMAP content of foods has greatly advanced our understanding of food composition. FODMAP composition is affected by food processing techniques and ingredient selection. In the USA, the use of high-fructose corn syrups may contribute to the higher FODMAP levels detected (via excess fructose) in some processed foods. Because food processing techniques and ingredients can vary between countries, more comprehensive food composition data are needed for this diet to be more easily implemented internationally.

Extrat from the study:
A – “ omissis The Monash University Department of Gastroenterology has performed extensive work for over 10 years to quantify the FODMAP composition of hundreds of foods. Foods tested for FODMAP content represent a range of categories, including fruit and vegetables; grains, cereals, pulses, nuts, and seeds; dairy products and dairy free alternatives; meat, fish, poultry, and eggs; fats and oils; beverages; and condiments and confectionary. Some of these data have been published previously (12 -14) and are summarized in Figs 1 and 2. With growing international interest in the low-FODMAP diet, our program of FODMAP food analysis is expanding to include more international foods. This paper will dis- cuss the criteria for classifying food as low in FODMAPs and the challenges encountered in analysing food for FODMAP content.

Bakary products and gluten-free

by luciano

The main problem of gluten-free products is to create a protein network within the flour proteins so that final products met the consumer’s expectations concerning texture and appearance of the fresh bread.
To achieve this purpose they are used:

1. hydrocolloids for building an internal network able to hold the structure of fermented products;
2. different crosslinking enzymes such as glucose oxidase (1), transglutaminase and laccase to create a protein network within the flour proteins.

A – Extract from: “Gluten-Free Products for Celiac Susceptible People. Sweta Rai, Amarjeet Kaur and C. S. Chopra. “

TECHNOLOGICAL APPROACHES FOR MIMING GLUTEN IN GLUTEN-FREE BAKERY PRODUCTS
The formulation of gluten-free bakery products is still a challenge to both for cereal-cum-baking technologists. Replacing gluten functionality has been a challenge for food technologists. The absence of gluten leads to weak cohesion and elastic doughs which results in a crumbling texture, poor color, and low specific volume in bread. Hence, during the last few years, numerous studies have been attempted for improving the physical properties of gluten-free foods, especially baked and fermented foods, by utilizing the interaction of the many ingredients and additives which could mimic the property of gluten (28). Approaches proposed for obtaining gluten-free baked foods include the utilization of different naturally gluten-free flours (rice, maize, sorghum, soy, buckwheat) and starches (maize, potato, cassava, rice), dairy ingredients (caseinate, skim milk powder, dry milk, whey), gums and hydrocolloids (guar and xanthan gums, alginate, carrageenan, hydroxypropyl methylcellulose, carboxymethyl cellulose), emulsifiers (DATEM, SSL, lecithins), non-gluten proteins from milk, eggs, legumes and pulses, enzymes (cyclodextrin glycosyl tranferases, transglutaminase, proteases, glucose oxidase, laccase), and non-starch polysaccharides (inulin, galactooligosaccharides) (Table 1). Strengthening additives or processing aids has been fundamental for miming gluten’s iscoelastic properties (93), where mainly hydrocolloids have been used for building an internal network able to hold the structure of fermented products. Simultaneously with the same intention, different crosslinking enzymes such as glucose oxidase, transglutaminase, and laccase have been used to create a protein network within the flour proteins (94). However, the success of gluten-free products relied on the type of effect of the enzymes as gluten-free processing aids, type of flour, enzyme source, and level. Generally, the combinations of ingredients and the optimization of the breadmaking process have resolved the technological problems, yielding gluten-free products that met the consumer’s expectations concerning texture and appearance of the fresh bread (95).